辽河油田超稠油蒸汽驱技术界限研究与应用

超稠油的黏度超过了蒸汽驱黏度界限,通常被认为不适合蒸汽驱开发,实际上超稠油蒸汽驱存在启动温度,当油藏温度超过启动温度后,蒸汽驱可以实施。针对辽河油田曙一区超稠油蒸汽驱技术界限认识不清的问题,运用室内实验及数值模拟手段,建立了蒸汽驱启动温度模型,并利用经济效益法建立了不同油价下经济极限产油量预测公式。研究表明:曙一区超稠油蒸汽驱的启动温度为80～100 ℃;在2 248 元/t油价下,最低产油量界限为2.5×10⁴t,油层厚度下限为14～18 m。以先导试验为基础,确定了单井最大产液量和最低注汽量的界限,优化设计蒸汽驱采用井距为70 m的反九点井网。目前已在曙一区兴Ⅱ—Ⅴ油层组优化部署了436个蒸汽驱井组,预测转驱后采收率为62.1%。该研究对同类油藏开发具有重要意义。

Research and Application of Steam Flooding Technical Limit for Super Heavy Oil in Liaohe Oilfield

Super heavy oil exceeds the viscosity limit of steam flooding and is generally considered unsuitable for steam flooding development. In fact, the steam flooding for super heavy oil has a threshold temperature, and steam flooding can be implemented when the reservoir temperature exceeds the threshold temperature. Aiming at the unclear understanding of the steam flooding technical limit for super heavy oil in Shu-1 block of Liaohe Oilfield, a threshold temperature model for steam flooding was established using laboratory experiment and numerical simulation methods. And a forecasting formula of the lowest oil production limit under different oil prices was also established using economic benefit method. The research results show that the threshold temperature for steam flooding in the Shu-1 block ranges from 80 ℃ to 100 ℃; at an oil price of 2 248 yuan/t, the minimum oil production limit is 2.5×10⁴t, and the minimum oil layer thickness limit is 14-18 m. Based on the pilot test, the limits of the maximum liquid production and the minimum steam injection rate of a single well were determined, and the well pattern for steam flooding was optimized to be inverted nine-spot pattern with a well spacing of 70 m. At present, 436 steam flooding well groups have been optimally deployed in the Xing Ⅱ-Ⅴ oil layer group in Shu-1 block, and the recovery rate after steam flooding is predicted to be 62.1%. This research is of great significance to the development of similar reservoirs.